Big Epp Just a word of caution about live uncured road kill type of free resources. Organics like tails, feathers, furs have a natural tendency to carry with them bugs parasites larva etc. Some still have active degrading fleshy left overs. Do some research about prepping them or treating them to avoid un wanted elements creeping into your other materials possibly ruining a high priced cape or hackle collar. Some people will micro wave ( radiate) tails and fur to kill unwanted unseen pests, (not in your personal home cooking micro, use a cheep older one dedicated to only that use)... some people cure tail ends with salt to dry them up to stop wrought and odors. A lot of people protect there stuff by storing it in moth balls after treating. A some what seemingly free road kill tail can cost you a ton of lost money and material if untreated or properly prepped . I am sure your probably already aware of this but thought it might be worth a mention. I have used road kill racoon tail and grey squirrel tails ,deer tails with good success and yes you can save money by doing so.
As you get further into the addictive qualities and free your creative spirit of tying. I found it so much more fulfilling and less work with piece of mind to purchase already treated products from specialty suppliers. Yes some what expensive to purchase but will last a very long time if you look after them. Bags of mixed craft stuff like feathers are very low quality in my experience and you have to sort out through a lot of substandard feathers to find the right size, length width ,lie barring etc not worth the time to me now . It is a process or evolution. I think it is limited to your budget and imagination Great hobby and pastime. Hope this helps. Happy tying.